1. Field of the Invention
The present invention relates to a method of examining or checking a degree of monocular diplopia in a quantitative manner through a sight of a patient and an eye mark chart for use in such an examining method.
2. Related Art Statement
Monocular diplopia is a kind of double vision in which even when an object is viewed with a single eye, double vision images are observed. In the past, the monocular diplopia was scarcely observed, but recently the monocular diplopia due to generally caused deficient in refraction of optical system of an eye has been diagnosed frequently. A degree of double vision does not appear constantly, but has been found to change in a day. Monocular diplopia is caused by astigmatism accompanied by presbyopia, and thus highly aged people have frequently suffered from monocular diplopia. Therefore, it is preferable to provide a useful eye mark chart by means of which a patient can easily examine monocular diplopia in a quantitative manner.
There have been announced many studies about monocular diplopia and there have been proposed several methods of examining monocular diplopia by directly inspecting an optical system of an eye. However, any method has not been proposed to examine a degree of monocular diplopia quantitatively in an easy manner by utilizing sight of a patient.